Carburetor



ff grfrffff c. J. GUsTAFsoN CARBUREIOR Filed April 13. 1921 April 5,1927.

Patented Apr. v`5, 1927.

UNITED STATES PATENT oFFicE.

CHARLES J'. GUSTAFSON, vOF CHICAGO, ILLINOIS, ASSIGNOR TO STROMBERG MOTOR DEVICES COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

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Appucaan mea Aprn 13, 1921. serial No. 461,003.

The present invention relates to carburetors, and has particular reference to an improved construction of valve for carburetors.

In its more fundamental aspect the-inven.

tion has reference to means for operatingv and controlinn a valve, and thisl aspect of the invention thas applicability to different types of carburetor valves designed for different purposes. ing and control principle can'be embodied with advantage in an auxiliary air inlet valve for regulating the admission of aux iliary air to the mixing chamber; or, it may be embod'ed with equal ladvantage in the form of an expanding and contracting venturi for controlling the velocity and volume of air flowing pastthe point of fuel injection in the carburetor.

One of the primary objects in devising the preent form of valve is to provide a construction which will not flutter or chatter under the suction pulsations of the engine. Furthermore, to provide such a valve which r will not be opened or closed or otherwise shifted in yposition by road shocks, jars or vibrations.

A further object is to provide a construction of valve which can be readily adjusted from the dash, steering column or other convenient point .for securing different operat ing characteristics of the valve. For starting and warming up a cold motor the valve may be conveniently adjusted from the dash or steering column to remain closed at all engine speeds. As a further operating characteristic the valve may be adjuste whereby it will remain closed until a pre! determined suction corresponding to a. predetermined engine speed is attained, or whereby the extent of valve opening for any predetermined suction in the carburetor can be controlled.

A further object is to provide a construe tion of valve which is primarily responsive f of al fioat chamber 13. The ioat chamber to two differential fluid pressures, one o which is the suction in the carburetor and the other of which is a controllable fluid pressure which may be regulated in accordance with the desired operation of the valve. This secondary fluid pre'sure may be instantly adjusted to retain the valve closed during all speeds of the engine, or to render the valve sufficiently sensitive that it will open For example, this operat,

during the relatively low speeds of thereugine if desired; an infinite range of adjustments intermediate these two being also possible.

A still further object is to provide a balanced construction of valve the operation of which will not be retarded or infiuenced 4Figure 3 is an elevational view of a steering column control for the carburetor;

Figure 4 is a longitudinal sectional view through. the expanding .venturi embodiment of my invention; j

Figure 5 is a transverse sectional view of the same taken approximately on the plane of the line 5-5 of Figure 4;

Figure 6 is a fragmentary plan view illus- .trating a modified arrangement of the embodiment shown in Figures 4 and 5; and

Figure 7 is a fragmentary sectional view of van expanding venturi illustrating the manner in which it shifts the region of highest suction.

Referring to the auxiliary aii1 embodiment of the invention,-the carburetor comprises a main casing 7 which defines a carbureting chamber 8. A primary venturi 9 opens into this carbureting chamber, and a secondary venturi 11` is supported in the -carbureting chamber' concentric with. the primary ven turi 9. The casing 7 is formed with a circular cover portion 12 which closes the top` casting 13 is formed with a central tubular portion 14 sage into which the lower end of the primary venturi 9 extends. A float 15 surrounding the tubular portion 14, controls a valve 16 at the fuel inlet opening 17, thus maintains the fuel atsubstantially the dash and dot level indicated. A fuel nozzle forming a continuous air pas- 105 and through the tubular portion 14. Thevlower threaded end 18 o`f the fuel nozzle projects through the bottom of -the air horn 21 for the reception of a nut 22 by which the air horn is clamped to the bottom of the float chamber bowl. A manually operated choker s valve 23 is preferably disposed in this air horn 21. A throttle valve 24 in the upper part of the carburet-ing chamber 8 controls t-he flow of the mixture from the carburetor.

Y The foregoing is descriptive of a conventional form of carburetor chosen merely for the purpose of illustration, it beingunderstood that my improved valve mechanism may be embodied in any desired form of carburetor.

Referring now to the auxiliary valve construction, it will be noted that the casing 7 Vis formed with a laterally extending air passage 25 which is adapted to discharge into the carbureting chamber through the secondary venturi 11. The end of this air passage 25 is formed with a cylindrical valve housing 26 which is closed at one end by an integral end wall 27 and at the other end by a removable cover plate 28 which is secured to the housing by screws 29. Rotatably mounted in this cylindrical housing is a cylindrical air valve 3() comprising two end heads 31-31, bearing against the ends of the j valve housing. The intake opening for this `air yalve is formed by a longitudinal slot 32 extending substantially across the bottom of the valve housing 26, the location of this air intake in the bottom of the housing being of advantage for the reason that it causes a continuous upward sweep of the air through the passage 25 and up into the secondary venturi 11. This is the preferred location of the intake opening 32 for the-avoidance of eddy currents in the air stream, although, of course, this intake opening can be positioned in the top, side or end 'of the valve housing if desired. This intake opening is controlled by a segmental rib 33 extending between the end heads 31--31 and normally lying over the intake opening 32. In the closed position of the valve thegforward edoe of the valve segment 33 contacts with tlie adjacent edge of the intake opening 32 as indicated at 69. The valve has bearing support on an axial shaft portion 34 which is formed integral with the end heads 31-31,

an-d which is provided with projecting end portions 34 supported in hubs 35 at the opposite ends of the valve housing. A movable wall 36 projects upwardly substantially radially from the shaft or hub portion 34, this movable Wall being formed integral with the hub portion and the end heads 31. An arcuate, tail segment 37 extends rearwardly from the upper end of the movable4 wall 36, to provide an extensive bearing or leakage preventing surface for cooperating with the inner periphery of the valve housing for the purpose of reducing the leakage past the wall 36. This wall 36 constitutes the movable wall of a retarding chamberc 38, the stationary wall of which is defined by a plate or vane 39. This stationary plate 39 is inserted radially into'the valve housing through a slot 41 extending longitudinally of the housing, the ends of this stationary wall bearing against or being in close proximity to the end heads 3l. 31.

`The inner edge of this plate or wall bears along the hub portion 34, and the outer edge is formed with a depending flange 42 which laps over the outside of the valve housing and is securedy thereto by screws 43. A balancing wall 45 projects radially from the hub portion 34 down into relatively close proximity to the valve segment 33, an opening permitting atmospheric air which has leaked into the area behind this latter Wall to be drawn into the air passage 25. Thev opening 50 may be made with different areas, the area being dependent -upon the balancing effect. desired and the degree of leakage from the atmospheric chamber 38 into the area 60. The atmospheric or retarding chamber 38 has communication with atmosphere thro-ugh a. portv 44 located intermediate the ends of the valve housing and communicating with the air passage 46 in the vent valve housing 47. This vent valve 'housing may be formed integral with the valve housing 26 or may be secured thereto in any preferred manner. A vent valve 48 reciprocates in an enlarged bore 49, the tapered lower end of this valve being adapted to cooperate with a valve seat 51 at the upper end of the airpassage 46. Lateral air ports 52-52 afford venting communication between the passage 46, and the atmosphere. The valve 48 is adapted to be raised and lowered by a bell crank lever 53 which is pivoted between lugs 54 extending from the casing 47. The short'arm of this bell crank lever is forked, and is provided at the ends of its forked arm with pins 55 which engage in an annular groove 56 in' the upper end of the valve. The other arm of the bell crank lever has connection at 57 with a control wire 58 leading up to a control device on the dash or steering column in the drivers compartment. The wire 58 extends up through a tube 59 which is clamped in thc lill) split end of an upright arm' 6l. Figure 3 illustrates a conventional form of control comprising a control lever 62 having operating connection with the control wire 58.

The valve is normally heldin the position illustrated by a tension spring 65 which extends from a fixed post 66 on the carburetor and connects at its other end with an adjustable screw 68 threading through an arm 67. This arm has a clamped mounting on the projecting shaft end 34. By adjusting the screw 68 any desired tension may be impoed on the spring 65. A spring of only light tension is desirable. This tension can be adjusted in accordance with the rate of fuel feed from the jet 18 so as to admit auxiliary air to dilute the fiow of fuel at `a predetermined engine speed.

lVhen the engine speed is accelerated to the point where the flow of air through the primary venturi 9 can not satisfy the suction. a rarefied condition will develop in the auxiliary air passage and valve housing 26. Assuming the vent valve 48 to be in the position illustrated, as soon as the suction becomes suiciently strong to overcome the light tension of the spring 65 the valve 30 begins `to rotate. This results from the differencesv in pressure between the suction which is effective upon one side of the movable wall 36, and atmosphere which is cilective on the opposite side of the wall 36 through atmosphere prevailing in the chamber 38. The air is drawn out from behind the balancing wall 45 through opening 50 ata faster rate than it leaks into'the chamber4 60, but there is usually a'slight diierencev of pressure between the opposite sides of this balancing wall so that the wall exercises a certain balancing influence upon the main wall 36.F The resulting rotation of the valve moves the valve segment 33 outjof register with the valve port 32 and allowsv atmosphere to fiow into the passage 25 and up through the secondary venturi 11 to satisfy the suction and to properly proportion the mixture. With the vent valve 48 open all the way and a high suction in the carburetor, the air valve will open to its maximum or until the auxiliary air entering the valve Ihousing satisfies the suction therein to the point, at which the suction pull' von the movable wall 36 is evenly balanced by the spring 65. This position of the vent valve 48 will thus result in the air valve initiating its opening motion at relatively low engine speed and reaching a position of maximum opening at the higher engine speeds. This wide open position of the vent valve has the further action of reducing the retarding effect upon the valve so that it can open more quickly in response tov accelerations in engine speed. This` however, is not at the expense of the dash-dot action of the valve, owing tothe fact that the 'passage- 46 always imposes a suiiicient constriction to prevent fluttering of the valve, and the balancing wall always cooperates with the confined chamber to dampen any fluttering tendency of the valve.

Assume now that theatmospheric or vent valve 48 is adjusted from the steering column control to entirelyor substantially close the. passage 46 to the admission ot atmosphere. There is always some leakage from the atmospheric chamber 38 past the movable wall 36 and stationarywall 39. This leakage is more or less inevitable in a free working valve and becomes a desirable factor for controlling the operation of the valve. The degree of leakage may even be controlled by a restricted orifice. In the closed or substantially closed position of the vent valve 48 this leakage quickly draws the air from the chamber 38 so that there are practically equal pressures on both sides of the main wall 36. Consequently the air valve remains closed during -all engine speeds. This adjustment is desirable forstarting and quickly warming up a cold motor.

Various other operating characteristics of the valve may be obtained by intermediate adjustment of the vent valve48. For example, by restricting the admission of at- -mosphere to a relatively small amount' the opening motion of the valve will be retarded by the'slow ingress ot atmosphere through the vent opening with theresult that the valve will not be so quick to respond to accelerations in engine speed, but will delay opening until the accelerated engine speed has become established. A secondary result following from this position of the vent valve involves the leakage from the chamber 38 past the movable wall 36 and stationary wall 39. When the'vent valve inlet has been constricted to the point wherethe leakage from the chamber 38 is greater than the rate of admission of atmosphere thereto a rarefied condition will be maintained in the chamber 38 whichwill'neutralize or counterbalance to a limited extent the effect of the engine suction uponthe movable wall 36. Hence, with the vent valve in this constricted position a higher suction will be relill) l Il() quired in the carburetor before the air valve f will begin to open'. 'By adj listing the-degree of restriction at the vent valve the air valve may thus be made to 'open only upon the by the combined influence of the spring and chamber 38.' In all positions of the vent valve the chamber 38 and balancing wall 45 will always impose an effective dash-pot or dampening action upon the valve so that no fluttering or chattering of the valve will occur.

In Figures 4 and 5 I have illustrated my expanding Venturi construction as embodied in a horizontal type of plain tube carburetor, although it is to be understood that this construction of expanding venturi may be embodied in any preferred type of carburetor. In this form the main casing forms'the usual carbureting chamber 71 in the forward end of which is mounted the throttle valve 72. A tubular neck 73 projects centrally down into the float chamber bowl 74 which is clamped to the bottom of Ithe casting 70. The lower end of the tubular portion 73 is enlarged to form a dash pot 75 which extends into and is spaced from an annular cup 76. The lower end of the dash pot 75 and the end of the cup 76 are formed with abutting shoulders as indicated at 77, and a nut 78 threaded into the bottom .of the dash pot bears against the bottom of the cup 76 through a suitable packing washer 79. A tapered metering pin 81 is supported in a threaded shank 82 which screws up or down in the nut 78 and which is packed by a gland packing 83. rIhe fuel has entrance into the dash pot 75 through ports 84 which open into the cup 76 which communicates with the ioat chamber 74. A conventional arrangement of iioatf85 and valve 86 controls the admission of fuel to the ioat chamber 74 so as to maintain a level approximating that indicated by the dash and dot line. Air is admitted to the Venturi-like throat 87 through an air horn 88 which is bolted to the main casting 70, and which is provided with two opposed air inlets 89.

rIhe carbureting chamber 71 and the Venturi-like throat 87 are formed with vertical, straight-sided walls 91-4-91. rIhe bottom of the Venturi-like throat 87 isA defined by a straight casting 92 having a Venturi shaped profile, which casting lays in the bottom of the horizontal air passage, and is formed with a depending tubular neck 93 extending down into the tubular portion 73. The Venturi-like throat 87 is expanded and contracted by a swinging valve 94 which is pivoted for oscillatory motion between the parallel walls 91-91 upon a horizontal pivot pin 95. This-valve consists of a vaneV 96, extending in a generally horizontal direction which is configured in the formation of a Venturi throat, and a vane or wall 97 extending in a generally vertical direction whiehforms the movable wall of the retarding or atmosphere chamber 98. A valve chamber 99 is defined by a removable arcuate cover 101 which is formed with horizontal flanges 102 secured to the casting 70 by screws 103. This cover 101 supports a stationary plate 104 which defines the other wall of the chamber 98 and which extends into contact or approximate contact with the hub 105 of the valve 94. A tail segment 107 on the movable Wall 97 reduces leakage from the chamber 98; and a tail portion 106- on the Venturi-like valve 96 cooperates with a housing extension 108 .in closing the area above this valve. An opening 110 in the valve wall vents this area into the air passage. A duplicate arrangement of atmospheric inlet 46 and vent valve 48 is provided for controlling the admission of atmosphere through the port 109. The previous description of this vent valve will suffice to.

illustrate its operation in connection with the present embodiment.

The Venturi-like valve 96 is formed with an enlarged centrally disposed recess 111 in the upper end of which is pivoted a link 112 upon a pin 113. The other end of this link is pivoted by a pin 114 in the slotted upper end of a reciprocable fuel tube 115 which slides in the tubular neck 93. The upper end of this tube 115 is provided with a vertical fuel slot 116 opening toward the carbureting chamber 71. rIhe lower end of this tube is threaded externally for the reception of a piston 117 operating in the dashpot 75, and internally is provided with an orifice 118 Which cooperates with the metering pin 81. A diagonal passage 119 in the main casting 70 is adapted to register with a port 121 in the tubular portion 93 so as to neutralize any suction existing around the lower end of the fuel tube and thus prevent fuel from being drawn up around the out-side of the tube.

I may rely entirely upon the weight of the Venturi wall 96, and fuel tube 115 and the piston 117 as the active opposing force tending to retain the Venturi valve in the dotted line position in opposition to the force exerted by the suction on the movable wall 97. (Ir, as shown in Figure 6, I may employ a iight tension spring in addition so as to obtain a greater opposing force or to .insure against sticking or binding of the valve. In this latter form the spring 122 connects with an adjustable screw in the end of an operatingarm 123 fastened upon the extending shaft 95', the vVenturi-like valve 94 being secured fast to the shaft 95 in this instance.

rlheVenturLlike valve 94 has substantially the same principle of operation as that of the auxiliary air valve in the previous embodiment. IVith the vent valve 48 in its open position, the starting of the engine produces a suction in the carbureti-ng chamber 71 which acts upon the movable wall 97 to open the Venturi-like throat an amount proportionate to the degree of suction. Upon this upward movement of the valve 94, a considerable length of the fuel emitting slot 116 is brought into communication with the constricted Venturi-like throat, and the port 118 in the bottom of the'fuel tube is raised up to a point of reduced area of the tapered pin 81 so that a predetermined volume of fuel can be drawn into the fuel tube. With a given setting of the vent valve 48, each rise or fall in the suction results in a corresponding rise or fall of the Venturi-like valve 94, with the `consequence that a substantially definite ratio exists between the degree of suction and the effective area of the Venturi-like opening for practically the entire range of speeds.I This results in the flow of air through the Venturi-like throat being maintained at a velocity which will have maximum 4Vfuel absorbing or fuel atomizing A eliiciency. By regulating the vent valve 48 in the manner previously described adjustment may be made for controlling the responsiveness of the air valve to sudden accelerations in engine speed, and to control the 'degree of opening of the valve for any engine speedi Flutterino or chattering of the valve is entirely obviated by reason of the alternate suctions and pressures produced in the confined chamber 98, and also by reason of the dampenincr action of the piston 117 reciprocating in the dash pot 75. Simultaneously with the raising of the Venturi-like valve to satisfy the higher engine speeds, the fuel port 118 is raisel to a more reduced portion of the metering pin 81 so as to permit a definitely larger quantityof r fuel to be discharge-d from the fuel tube for producin a properly proportioned mixture. Thus t 1e fuel and air are jointly proportioned by the position of the Venturilike valve.

A particular feature of this expanding Venturi-like throat is the ability to cause the point of highest suction to shiftl along the axis of the air stream relative to the point of fuel injection, to thereby automatically proportion the mixture in accordance with the various demands of the engine. The existence of such shifting action and the degree of shifting for a given range of suctions can be regulated by the curvature and motion of the relatively movable Venturilike walls. In Figure 7 I have illustrated a design of Venturi-like valve which, from a relatively low suction to a relatively high suction shifts the point of greatest depression from the point a to the point b along the air stream. The point of fuel injection f, which ma consist of a constant jet, can.

be positione at any desired point along the air stream relative to the points a and b. For obtaining a decreasing proportion of fuel for the higher engine s eeds the oint of maximum suction may t us be/ma e to recede from the jet with the higher engine speeds, thereby automatically reducingthe v aspiration on the jet.

side,-and adjustable means for controlling the admission of atmosphere to said retarding chamber.

2. In a charge forming device, an air controlling valve, said valve being pivoted for oscillatory motion, a retarding chamber, a baflleoscillating with said valve and forining a movable wall on said retarding chamber, an atmospheric vent to said retarding chamber, and means for regulating said vent.

3. In a charge forming device, the combination of a valve chamber of generally circular formation, a rotary air controlling valve pivoted in said valve chamber, a movable baiile projecting from the axis of said valve and adapted to oscillate with said valve, a stationary baieprojecting into said valfve chamber and cooperating with said movable baffle, said baffles .deiining a retarding chamber therebetween, and means for controlling the eective pressure in said retarding chamber.

4. In a charge forming device, the combination of a valve chamber of generally circular formation, a rotary air `valve pivotally mounted in saidyalve chamber, an air inlet in said valve chamber, a valve segment normally covering said air' inlet, a movable4 bafiie for rotating said valve, said movable bale projecting onthe axis of said valve and cooperating with the inner wall of said valve chamber, a relatively stationary baile projecting inwardly in said valve chamber to substantially the axis of said valve, said movable andstationary bafiles deining an arcuate retarding chamber therebetween, an

atmospheric inlet for said retardin chamber, and adjustable valve meansy or controlling said inlet.

5. In acharge forming device, the comhousing communicating wit said chamber, an auxiliary air port in said valve housing, a rotary valve in said valve housing, said rotary valve comprising a valve segment forA revolving into and out of register with said auxiliary air port, said rotary valve com- `bination of a chamber, a c lindrical valve prising a shaft portion extending axially through said valve housing, and moving with said valve, a substantial radial baffle projecting from said shaft portion and engaging With said valve housing, said bale being adapted t0 move with said valve for operating the latter, a relatively stationary bafHe projecting substantially radially from said valve housing to said shaft portion, said movable and stationary bailes defining an arcuate retarding chamber, said movable baffie being subjected on one side to the suction in said valve housing and on the other side to the pressure in said retarding chamber, an atmospheric' inlet to said retarding 15 chamber, and an adjustable valve for controlling the admission of atmosphere through said inlet.

In Witness whereof, I hereunto subscribe my name this 7th day of April, 1921.

CHARLES J. GUsTAFsoN. 

